PURPOSE: To prevent the cracking on the road surface due to the cold air by burying a radiating pipe made of corrosion-resistant synthetic resin in the road surface, storing heat in the road surface with the hot spring waste hot water precipitation/filtration- treated and set to a specific temperature, and keeping the road surface at the freezing point or above to melt snow and prevent freezing.

CONSTITUTION: The high-temperature waste hot water in a bathtub 1 is guided to a precipitation tank 2, and an iron net 5 for concurrently preventing the occurrence of cracks on the road surface 3 and accelerating heat conduction is bound and fixed to a radiating pipe 4 above or below the radiating pipe 4 made of a corrosion-resistant synthetic resin pipe and buried in the road surface 3. When the temperature of the road surface 3 becomes 0°C or below or a snowfall detector detects a snowfall in winter, the hot spring waste hot water with the temperature 20-35°C is fed to the radiating pipe 4 in the road surface 3 through a filter 7 such as a hair catcher via the natural flow or with a pump 6 at the proper flow speed in proportion to the snowfall strength or atmospheric temperature reduction quantity. The road surface 3 is kept at 0-2°C, the snow accumulated on it is melted, the freezing of the road floor 10 is prevented, and the cracking on the road surface 3 can be prevented.